"Good" Bacteria Drives Intestinal Response to Infection

OCTOBER 06, 2008

Findings from a recent study by Yasmine Belkaid, PhD, and colleagues in the Laboratory of Parasitic Diseases at the National Institute of Allergy and Infectious Diseases (NIAID) have found that “good” bacteria (commensals) that normally live in the intestines may actually help the body defend against infection. The study, which became available online on October 2 in the journal Immunity, describes a way in which T-cells “are regulated to facilitate an immune response to a pathogen” and also explains that researchers found that “during an infection, the DNA of the body’s beneficial bacteria binds to a specific receptor on the intestinal immune cells, called TLR9.” The DNA acted as a natural adjuvant and boosted the activity of T cells so that they could destroy the invading pathogen.

"There is a balance of regulatory immune signals in the body," noted Dr. Belkaid. "During an infection, we’ve found that commensals can break this balance in favor of an infection-fighting response."

Exactly how commensals protect against pathogens has yet to be fully understood. However, if more research can determine how this interaction occurs, it would open up the possibility of using beneficial bacteria as a target for oral therapies against infections and autoimmune diseases.